Ferguson Police Chief Tom Jackson is surrounded by his officers as he leaves a news conference in Forestwood Park on Friday. Jackson took questions in the quiet park after earlier identifying Darren Wilson as the officer who shot Michael Brown.

FERGUSON, Mo. — Police on Friday identified the officer who fatally shot an unarmed black teenager and released documents alleging the young man had been suspected of stealing a $48.99 box of cigars from a convenience store in a “strong-arm” robbery shortly before he was killed.

Police Chief Thomas Jackson said the officer did not know the teen was a robbery suspect at the time of the shooting and stopped Michael Brown and a companion “because they were walking down the middle of the street blocking traffic.”

Darren Wilson, a 28-year-old white officer, has patrolled suburban St. Louis for six years and had no previous complaints filed against him, Jackson said.

Brown’s relatives said no robbery would justify shooting the teen after he put his hands up. Family attorneys said Brown’s parents were blindsided by the allegations and the release of a surveillance video from the convenience store.

“It appears to be him,” attorney Daryl Parks said, referring to the footage, which he said was released without any advance notice from police.

The police chief described Wilson as “a gentle, quiet man” who had been “an excellent officer.” He has been on the Ferguson force for four years and served prior to that in the neighboring community of Jennings.

Wilson, who was placed on administrative leave after the Aug. 9 shooting, “never intended for any of this to happen,” Jackson said.

According to police reports released Friday, authorities received a 911 call at 11:51 a.m. on the day of the shooting reporting a robbery at the Ferguson Market. An unidentified officer was dispatched to the store, arriving within three minutes. The officer interviewed an employee and customer, who gave a description of a man who stole the cigars and walked off with another man toward a QuikTrip store.

Descriptions of the suspect were broadcast over the police radio. The officer did not find the suspects either on the street or at the QuikTrip, the reports said.

The robber took a box of Swisher Sweets, a brand of small, inexpensive cigars. The suspects were identified as 18-year-old Michael Brown and 22-year-old Dorian Johnson, according to the reports.

Separately, Wilson had been responding to a nearby call involving a sick 2-month child from 11:48 am until noon, when he left that place. A minute later, he encountered Michael Brown walking down Canfield Drive. The documents contained no description of what happened between Brown and Wilson.

Johnson has told reporters that the officer ordered him and Brown onto the sidewalk, then grabbed his friend’s neck and tried to pull him into the car before brandishing his weapon and firing. He said Brown started to run and the officer pursued him, firing multiple times.

Another family attorney, Benjamin Crump, noted that police did not release a photo of the officer but released images from the store’s security video that they say show Brown grabbing a man inside the store. Crump said he had not seen the photos.

Police “are choosing to disseminate information that is very strategic to try to help them justify the execution-style” killing, said Crump, who also represented the family of Trayvon Martin, the teenager fatally shot by a Florida neighborhood watch organizer who was later acquitted of murder.